Water Under The Bridge
by thecarouselneverstopsturning
Summary: Scandals, lies, cheating wives, babies that are not yours, interns, ex-best friends who are the actual father of the baby your wife is carrying. AU in which Addison kept Mark's baby, but let Derek think it was his child. What happens when the truth is found out? Season Two, one-shot. Maddison with lots of MerDer, not really any Addek, MerAddie friendship, Gizzie, Calzona, Burktina.


**Hey, I just thought of this like yesterday.**

 **It is a one-shot and it's kind of based on If/Then but it's twisty, because while Addison didn't abort Mark's baby, she still went in an attempt to get Derek back and allowed him to think it is his while it's not just like in the actual episode, but it's actually set in Season 2.**

 **Other changes: Mere and Derek did meet at the bar and dated, then his wife shows up pregnant...with his best friend's baby and ruins it all. Maddison dated way before she met McDreamy, maybe I'll add Emma to the mix plus they were friends with benefits for all these years just like in my other story.**

 **We start at around Yesterday, after McSteamy arrives. It takes place 5 months after she shows up but I'm not sure actually as I don't like Season 2.**

 **There is Maddison, MerDer, and a little Addek though not much because I don't like them at all, but I'll try my best. Maybe some Burktina but they're side characters.**

 **One last thing: I made Addek married two years less so they've only been married for nine years to fit in with the story because the timeline is really out of whack and Sloane does not exist.**

 **Let's go on.**

Derek walked into the lounge to find Addison crying. "I... I don't know what's wrong with me. All I know is that the baby's coming, and I want it. It may change things. You'll get happier. We'll just take it one step at a time. I wanna make it work." He said.

"It isn't your baby." Addison confesses.

The actual father of the baby and Derek's best-friend, Mark is leaving the bathroom shirtless. "Oh... This is awkward." he exclaims.

"Are you going?" Derek asks.

"I am. Derek, I'm probably leaving. I'm probably going back to New York with Mark." Addison agreed.

'Derek, I'm sorry but you and I, we're never...we're never gonna be friends again," Mark begins, "So let's start fresh. Addison's miserable; I'm miserable without her. This is what has to happen."

'You can have her." Derek walked out. "I will send you the divorce papers tomorrow morning." he adds before walking out.

"OK." Mark confirmed.

"Yeah." Addison smiles.

Derek was walking when he got stopped.

"Aren't you supposed to be with your wife?" Meredith asks him.

"The baby is not mine," Derek admitted.

"Then whose baby is it?"

"Mark Sloan's." he confesses. "I can't believe that out of all these months, she's been lying to me!" he exclaimed as realization creased on him. "She lied to me. I bet she was fucking my best friend before we met and all the nine years we were married."

"Oh, Derek." Meredith hugs him.

"Thanks Mere."

"You're welcome."

When the stick turned blue, Addison knew that her husband was not the father.

Mark was with her quite frequently and it was a spur of the moment. Her husband hasn't touched her since he had become absent and a relationship between her and Mark resurfaced from the affair.

She wanted her husband's attention but as soon as she found out about that baby, she realized that was not how she wanted his attention.

Mark would've been a terrible father and was fucking a Peds nurse, she knew so as soon as Richard called her, she had jumped on a plane in an attempt to get Derek back and now here she is.

She knew his heart was not with her anymore- his heart was with Meredith Grey.

Her baby kicked and she smiled at the movements, placing her hand on her belly.

Derek couldn't believe this, his wife had been pregnant with Mark's baby all this time and kept it a secret from him.

Allowing him to think it is his child when it was really his best friend's kid.

Has he made a mistake picking Addison over Meredith when he had picked her over the woman he really loved?

He didn't follow his heart and picked the adulterous bitch of a cheating wife over the soft-spoken, beautiful, extraordinary, intern.

And now he was regretting it because the signs were there.

"How's the wife?" Richard asks.

"It's not my baby." Derek confessed.

"Well then whose baby is it?"

"Mark Sloan's."

"Your best friend?"

"My best friend right up until he had sex with my wife and got her pregnant."

"I didn't think Addie was capable of cheating."

"Me too. Guess some people think wrong."

"Derek! Please." He heard Addison call out after dragging him to a stairwell. "We can talk about this."

"NO!" Derek dismisses her. "You are pregnant with another man's baby. I don't wanna talk to talk about it, end of story."

"I'm sorry... I'm sorry. You have to give me a chance... you have to give me a chance to show you how sorry I am..." Addison said and tries to kiss him.

"OK..." Derek replies uneasy as he pushed her away.

"OK?"

"I'm gonna go, you find a place to stay. I'll send you the divorce papers in the morning."

"No, no, no... We can survive this. Derek, we can survive this. We're Addison and Derek."

"I look at you and I feel nauseous. We're not Derek and Addison any more. We're done."

"If you go now... If you divorce me we're not going to get through this. If you go now, we don't have a chance... we don't have a chance." Derek walked away. "What an ass."

Derek walked into an on-call room and dialed a number. Weiss picked up.

 _"What's up?"_

"I'm getting a divorce!" Derek blurted out.

 _"What?"_

Derek then proceeded to tell him everything.

 _"You shithead!"_

"I know, I know." Derek then got a 911. "I gotta go." He hung up the phone and walked out.

The next day, Bailey is giving out orders.

"Grey, you are with the female Shepard, Karev, pit, Yang, we are clearing the docks, I need you to write discharge papers, Stevens, you are with the male Shepard, and O'Malley, you are with Burke." Bailey walked away.

"So I heard McWife is pregnant with McSteamy's baby?" Cristina questions.

Meredith nodded as Alex spoke up. "They need nicknames." he said.

"Like Evil Spawn and Bambi?" Cristina sneered.

"No. He means like names we should call them." George chimed in.

"I got one!" Izzie perkily exclaims and they awaited her answer. "Good Shepard and Bad Shepard." she grinned.

"Who is gonna be who?" Alex asks.

"McWife is Good Shepard and McDreamy is Bad Shepard."

"I like it." they all agree as the exact woman they were taking about, walked up.

"Grey?" Addison asked and Meredith followed her into one of her exam rooms.

"Where is the patient?" Meredith asked.

"I am the patient." Addison points out as she hopped up on the table and pulled her scrub top up. "I need you to give me a sonogram." she clarifies as Meredith turned on the ultrasound machine.

"Do you want me to tell you the gender?" Meredith said, not so scared of her ex-boyfriend's wife anymore.

"No wait until Mark shows up." Addison took out her phone and texted him then they sat in silence. "I don't hate you, you know." she says.

"I know." Meredith answered.

"Addie, baby!" Mark rushed in five minutes later. "Look my adulterous buddy," he said pointing to Meredith.

Meredith ignored him. "Do you guys want to find out the gender?" They nod. "Addison, would you like to tell Mark or would you like me too?" she asks as a picture of the baby showed up.

"I'll do it." Addison agreed. "Mark, it's a girl." she grinned.

"Wow Red, that is our baby girl." Mark was smiling so hard that it looked like his face was going to split into two.

It was a month later and Addison and Derek's divorce hasn't been finalized yet. Addison and Meredith are becoming friends now.

"Miranda, I need a consult." Addison said.

"I'm not working." Bailey points out as Tuck looks at the red-head.

"Miranda, I need a consult!" Addison said again but a little more angrily.

Meredith was having a bad day and didn't get a chance to check out a patient because Addison yanked her into an exam room.

"This is what I get!" Addison cries as her legs were in stirrups and a blanket was covering her to give her privacy.

"What the hell?" Meredith questions.

"You're supposed to be my friend and why can't you be happy for me?" Addison cried.

"My biggest issue is that you haven't divorced Derek yet, how am I supposed to be happy for you if you haven't divorced him yet? And I'm supposed to be looking at my patient's stats!" Meredith went crazy as she looked at the two women, "And how the hell did you get poison oak on your vajayjay, Addison?" she questioned.

"I went running the park and I had to pee because I'm pregnant and have a baby sitting on my bladder and I'm huge so I squatted and now the universe is screwing me over. Now my husband won't talk to me because I'm pregnant with his best friend's daughter." she starts crying, "This is what I get!"

"Oh no," Bailey started to back away. "Please don't cry." she says.

"This is what I get, this is what I get!" Addison continued to cry as she points to her belly and then the sheet.

"Stop, you're gonna make me," Bailey put her hands on her chest and the whole area around it became dark. "Lactate. Grey, get gauze!" she commanded and Meredith ran out.

A month later, Addison had went into labor at two in the morning. Meredith and Derek were sleeping when her phone had rung.

"Doctor Grey." Meredith said tiredly into the phone.

" _Hi, I'm calling on the behalf of Dr. Montgomery. She is having her baby and requests you be there._ "

"Alright, I'll be there." Meredith hung up the phone, saw that she's gotten twenty frantic texts from Mark, grinned, and gently shook Derek awake. "We gotta go to the hospital."

"Why?" Derek asks.

"Addison's water broke and she is having the baby now." Meredith explained.

Derek got out of bed and started changing. "Fine but we will have to get Starbucks on the way." he peered over his shoulder.

"Deal." Meredith grins as she went into the bathroom to brush her teeth.

As soon as they had gotten to the hospital, Meredith ran up and hugged the older red-head. "I won't ask you how you're feeling." she smirks.

Addison smiled as a contraction hit. "Oh my god!" she gasped.

"Breathe, Addie. Breathe." Meredith cooed, thinking it was weird how she was helping her boyfriend's ex-wife, as she sipped her strawberries and cream fappuccino.

Mark walked in and Meredith handed him a bone-dry cappuccino. "So how is it going...Daddy?" she questions.

Mark grins and took the drink. "So...where did you get this?" he opened the lid and smelt it.

"Starbucks." Meredith points out.

"How thoughtful of you." Mark smirked as he grabbed his baby mama's hand.

Meredith turned her attention to the older red-head.

"Mark and I are getting married." Addison blurts out. Meredith hugged her again.

Addison was finally ready to have the baby at 8AM.

"Come on, Doctor Montgomery, it's time to give birth." her doctor said.

"Red, take my hand." Mark offered her his right hand because the left hand was more worth it.

Addison had a contraction, "Oh this baby better appreciate all the work I'm doing."

"She is Baby, and she loves you."

"Sloan why didn't you use a condom you dumb fuck?!"

"One more push." the doctor commanded.

Addison pushed one last time and let out an ear-piercing scream as she felt the baby slip out of her.

"Congratulations, Doctors. You've got a beautiful baby girl." the doctor held up the crying and vernix-coated baby.

"Look what we did, Mommy." Mark said as he laid their baby girl on Addison's chest after she was cleaned up.

Addison took her hand in hers and kissed it, feeling a sense of pride just like after she had given birth to their first child that Bizzy made her give up for adoption because she did not approve of her daughter having a Sloan's baby. "Hi little girl, I'm your mommy. I waited a very long time for you. You don't know what I had to go through to get you, Baby Girl." she looked into their girl's big blue-green eyes and it reminded her of their first daughter. She lifted their baby girl's hat and saw a beautiful shock of red hair, aligning her head.

"Thank you for my gorgeous baby, Red."

"No, Mark, thank you for my beautiful baby girl."

"Do you have a name?" the doctor asked.

"Yes," Addison looked at her baby then at her fiancé. "Ella Elizabeth Montgomery-Sloan."

"That is a beautiful name." the doctor smiled.

They didn't move to New York but they did get married then their first daughter Emma, from high school showed up. Pregnant when her sister was almost five.

Her parents wanted the baby but Emma decided to raise her baby on her own in Los Angeles so she moved in with Sam. The baby was a boy named Caleb who looked like a Mini-McSteamy which was a little weird considering Emma was a Mini-Addie; except for the nose which was the Sloan's nose.

She falls for Pete and they had gotten married, having twin girls named Lauren and Riley. They were Mini-Addie's too but one had straight green eyes and the other had cyan eyes. She'd adopted Lucas as well and became his step-mother.

Her parents had another girl named Chloe. She looks just like Addison did as a baby too.

Mark loved his girls but he ached for a little boy because his older girl did not give them her son. Soon another baby was welcomed into the Sloan family; a baby boy named Steven who looks just like his daddy. Everybody adored him very much and as he had gotten older, they called him a 'Mini-McSteamy' which they probably would've called his nephew but he is in Los Angeles with his family.

As for the other doctors, Derek and Meredith did get married too but she had problems getting pregnant so they had adopted Zola then they finally had Bailey and Ellis. Burke never left Cristina at the alter so they are married and had a son who is named Ryder. Callie and George got married and she did come out as gay so she married Arizona while he married Izzie, as for the moment, Alex is still single but he did have a child with Jo. Jackson and Lexie have a child too so April is still single also.

Addison smiled as she watched the kids and rested her head on her husband's shoulder and he placed a kiss on her forehead, thinking how this could've been her life if she'd only realized some things earlier but she knew she made the right choice with keeping Mark's baby all along and not telling him about Emma after her family had moved.

This is their life and she wouldn't have it any other way.

 **I hope you Maddison fans are out there because I haven't been seeing as much fanfictions of them and they are love so I'm little worried that their fandom is dying out. Yep, I added Emma in too and now I love her and Pete together but she didn't give her baby to her parents like she did in the other one, even though the premise is basically the same.**

 **I tried to add as much Addek as I could but it's hopeless since even though, Addison is like my favorite character ever I could only imagine her with Mark so that's why I do not like Season 2 or Slexie much ether.**

 **I hate Addisam, kind of don't like Jaddison, and hate Paddison too but Addek is the worst though Addisex is just as bad. I hope people will agree with me on that and that Maddison should be endgame instead and she never should of left and aborted the baby, plus Sloane never ever should of existed or found out about her presence. MerDer, Calzona, Jaxie, Burktina, Tenry, and Gizzie, are complete endgame too even though Crowen, Japril, CaGe, Dizzie and Crackson are too.**

 **So tell me your thoughts and if you want me to do anymore like this and you have any suggestions, I take any type of feedback but not too mean; I'm only a teenager :)**

 **Question for you guys: Have any of you ever read Romeo and Juliet and/or watched the 1968 version?**

 **I read the book and watched all versions but the 1968 is the best.**

 **I love Olivia and Leonard; they are great and beautiful and What is a Youth at the masquerade party is adorable, so is Benvolio.**

 **Review!**

 **Oh and check out my other stories:** **Our Love Can Do Miracles, All in the Family, Out of The Rain, etc.**

 **If you're interested in FRIENDS then check out: Delightful, Mio Amore, Sea Blue, This is Our Life, Our World, Happily Married, Faithfulness, etc. (Warning: I haven't updated any of those in a year)**

 **Thanks :)**


End file.
